There are a number of commercially known fluid solid processes which are conducted at high temperatures and which require removal of particulates from effluent gas streams. A representative example of such processes is the fluidized catalytic cracking of petroleum feedstocks. Fluidized catalytic cracking units employ both a reactor vessel and a catalyst regenerator vessel, each of which includes cyclones for the recovery of catalyst particulates from the gases emanating from these vessels.
Those particulate recovery systems in which a solids entrained gas stream passes first to a cyclone separator for removal of particulates and thence to a manifold for exiting the vessel are called single stage cyclone systems. Since single stage cyclone systems are not sufficiently efficient to meet todays particulate recovery requirements, it is known to couple the outlet of a first stage or primary cyclone separator to the inlet of a second or secondary cyclone separator thereby providing a two stage particulate recovery system of high efficiency. Catalyst regenerator vessels in fluid cat cracking units is one such example of a two stage particulate recovery system.
Because of the geometrical constraints imposed upon the location of the cyclones within the vessels having two stage particulate systems, the thermal stresses between the cyclones and reactor internals resulting from the higher temperature conditions existing within the vessel during operation tend to be exaggerated. Hence, stress compensating techniques are required for suspending the cyclones to avoid downtime for maintenance and correction of mechanical failures. A number of stress compensating cyclone suspension techniques are disclosed, for example, in the Oil and Gas Journal, Apr. 29, 1985, pages 71 to 79; U.S. Pat. No. 4,287,158, U.S. Pat. No. 3,951,629 and U.S. Pat. No. 3,333,402.
Notwithstanding the numerous techniques used to suspend cyclones in vessels, there still remains a need for improved techniques for suspending such cyclones which will maximize the use of ordinary shop fabricated parts that can easily be lowered in the vessel thereby eliminating the need for field welding, on site fabrication, and the like.